NASA Earth Observatory image; turbid plumes of the Mississippi flowing into the Gulf of Mexico

On this leg, 11 geochemists gathered together to study the influence from the high discharge of the Mississippi river into the ocean. The coastal zone of the Gulf of Mexico is suffering badly from human induced eutrophication. Satellite images already provide us with a lot of information from the situation. However, what the geochemists want to unravel is the invisible part: the consequences for the deeper ocean. Studies have been done here before by other institutes, but not in a way that all aspects were studied and linked together in one research. Until now, studies are mostly done with computer models. But our research will be based on field data linking sediment dynamics with the water column.

Our team has also designed a unique transect, moving over the continental shelf from shallow waters towards the deeper waters. The Mississippi discharge material and their influence on ocean and sediment dynamics are our focus. Surprisingly, an investigation in this way has not been done in this area before. An area which is in desperate need for attention.The combination of eutrophication and weak summer winds, creates the second largest “dead zone”, in the global ocean during summer. Our research is likely to be influenced by the hypoxic (poor in oxygen) phenomena.  However, we do not know how that will look, or what else we might find. Think about the possibility of the presence of cable bacteria, or traces of the oil disaster of 2010. But more horrifying; recently the highest sea surface temperatures and sediment discharge were measured in this area for spring time. Will this lead to an even greater hypoxic zone this summer? It is going to be an interesting investigation. Another investigation towards the unknown from the NICO expedition.

Roosmarijn van Zummeren – MSc. Student Marine Sciences – Utrecht University